Automotive rotary electric machine

Abstract

The present invention provides an automotive rotary electric machine enabling brush abrasion limit detection reliability to be increased and stable brush abrasion limit detection indication to be performed. The construction thereof is provided with a detecting terminal for sensing a brush abrasion limit when a brush has abraded to a predetermined length by coming into contact with a coil spring that forces the brush, and a determining circuit constructed so as to compare output from the detecting terminal and a threshold value, to enter an ON state (a brush abrasion limit detection state) once the output exceeds the threshold value, and thereafter to maintain the ON state. Thus, because the ON state of the determining circuit is maintained even if output from the detecting terminal fluctuates due to vibration, noise, etc., false detection of the brush abrasion limit resulting from the fluctuations in the output from the detecting terminal can be prevented.

1. An automotive rotary electric machine comprising:
 a rotor having:
 a field winding for generating a magnetic flux on application of an excitation current; 
 a plurality of magnetic poles magnetized by said magnetic flux; and 
 a current receiving portion electrically connected to said field winding; 
 
 a power supply mechanism portion having:
 a brush in contact with said current receiving portion; 
 
 a brush abrasion limit sensing portion for sensing that said brush has abraded to a predetermined length; 
 a brush abrasion limit detecting means constructed so as to monitor an output from said brush abrasion limit sensing portion, to enter a brush abrasion limit detection state at a point in time when said output exceeds a set value, and including switching means for thereafter maintaining said brush abrasion limit detection state regardless of whether said output exceeds said set value; 
 a stator having a stator winding in which an electromotive force is generated on application of a rotating magnetic field accompanying rotation of said rotor; and 
 a controlling means for controlling an output voltage from said stator so as to be constant, 
 wherein said brush abrasion limit detecting means and said controlling means are constructed in a single integrated circuit. 
 
   
   
     2. An automotive rotary electric machine comprising:
 a stator having a stator winding; 
 a rotor having:
 a field winding for generating a magnetic flux on application of an excitation current; 
 a plurality of magnetic poles magnetized by said magnetic flux; and 
 a current receiving portion electrically connected to said field winding; 
 
 a power supply mechanism portion having: 
 a brush in contact with said current receiving portion; 
 a brush abrasion limit sensing portion for sensing that said brush has abraded to a predetermined length; 
 a brush abrasion limit detecting means constructed so as to monitor an output from said brush abrasion limit sensing portion, to enter a brush abrasion limit detection state at a point in time when said output exceeds a set value, and including switching means for thereafter maintaining said brush abrasion limit detection state regardless of whether said output exceeds said set value; 
 means for sensing at least one of a state of no power generation and a state of overvoltage by monitoring an output voltage of said stator, and 
 a controlling means for controlling an output voltage from said stator so as to be constant; 
 wherein said means for sensing at least one of a state of no power generation and a state of overvoltage is constructed in a single integrated circuit; and 
 wherein said brush abrasion limit detecting means and said controlling means are constructed in a single integrated circuit. 
 
   
   
     3. An automotive rotary electric machine comprising:
 a rotor having:
 a field winding for generating a magnetic flux on application of an excitation current; 
 a plurality of magnetic poles magnetized by said magnetic flux; and 
 a current receiving portion electrically connected to said field winding; 
 
 a power supply mechanism portion having:
 a brush in contact with said current receiving portion; 
 
 a brush abrasion limit sensing portion for sensing that said brush has abraded to a predetermined length; 
 a brush abrasion limit detecting means constructed so as to monitor an output from said brush abrasion limit sensing portion, to enter a brush abrasion limit detection state at a point in time when said output exceeds a set value, and including switching means for thereafter maintaining said brush abrasion limit detection state regardless of whether said output exceeds said set value; 
 means for sensing at least one of a state of no power generation and a state of overvoltage; 
 an indicating lamp; 
 wherein said indicating lamp is constructed so as to flash on and off when said brush abrasion limit detecting means detects a brush abrasion limit, and so as to be continuously lit when said means for sensing at least one of a state of no power generation and a state of overvoltage senses at least one of a state of no power generation and a state of overvoltage.